Pressure cooker



A. J. KIRSTIN PRESSURE COOKER May 8, 1951 5 Shuts-Sheet 1 Filed Sept. 4, 1945 7 INVENTOR.

dfi'ed JJZWFZZTU y 3, 1951 A. J. KlRSTlN 2,552,098

PRESSURE COOKER Filed Sept. 4, 1945 I 3 Sheets-Sheet 2 minim Illlll v @{m H L r IN V EN TOR.

A. J. KIRSTIN PRESSURE COOKER May 8, 1951 3 Sheets-Sheet 3 Filed Sept. 4, 1945 INVENTOR. w/flgd M715 Z676 Patented May 8, 1951 UNITED STATES PATEN r OFFICE] PRESSURE COOKER Alfred J. Kirstin, Peoria, 111., assign. to National 3 Aluminum Manufacturing. 00.,; Peoria, IlL, a corporation of Illinois Application September 4, 1945, Serial No. 614,147

My invention relates more in particular, to improved means for securing the covertothe pot of .suchpressure cooker;

Pressure cookers are known in which the cover and pot are locked-in position-by means .ofan expanding ring normally held in a groove on the outside of the pot but expandable partially into. a groove on the cover andwherein the joint between the pot and cover is sealed by a flexible sealing ring held tightly against such joint by the vaporpressure within the-pot. Such Stl'LlCr. tures require rotation of .the cover with respect.

tothe pot-to lock the two together and'in large sizes of pressure. cookers sufficient frictionmay:

develop between the sealing ringand rim of the pot .(particularly if a substance having :a

cementitiouseffect-should come in contact with the sealing ring) and unusual efiort may be required to remove the covenat the end ofaa cooking operation, Another disadvantage results fromthe fact that unless latching means of. some kind be provided, it is at times possible forthecover to become releaseddue to pressure, in. the'event the-user-of the device hasfailedto turn the cover" to fully locked position. This 'is due to the fact that when in locked position, the locking ring is under compression, one end being lodged against a stop'on the pot and the. other end' lodged in a stop on the'covere When ficulty is readily overcome, and,- in any event,

will not occur if the instructions are-followed in operation of the device, I have found 'a' simplemeans of so improving the locking mechanism as to avoid the described 'difiiculty. l have found that my improved locking arrangement may be employed in such a manner as toutilize turn-I ing movement of-the'cover for operation thereof or in such 'amanner that the locking'ringmay be turned independentlyfzof the cover. in accordance with the preferred arrangement described hereinbelow.

In carrying'out my. invention I the groove carrying'the locking ring, a plurality of *proj ectio'ns; conveniently pins; which extend;

to pressure cookers and,

provide, in

'2 Claims (01. 220- 1) I 2. into recesses or notches on looking ring. These notches are finished with a slanting shoulder on one side which acts as a camto permit the entire locking ring riding up on. the projections; when thelocking ring is movedato expanded position,- thereby positively holding the entire locking ring in expanded posiition. This cam arrangement may be provided in-several ways,.but the provision of. notches on the locking ring and projections in the nature of pins in the groove represent the simplest and most economical manner of carrying outthe idea which I-have been able to. devise. This arrangement" of locking ring may beemployed by anchoring one end of, the locking ring. against astopwonthe pot and providing an extending handle'on the other end for. expansion of the. ring independently of the cover; or one end," of the locking ring may be engaged by the. cover.

andoperatedbypartial rotation of the ;cover, if desired. 1 a

The objects and additional features of: the

invention will be further brought out in the following detailed description taken. with the accompanying drawings wherein: w Fig'il is a fragmentary perspective view -sh0W-' ing my invention applied to a pressure: cooker ofa type wherein the-locking ring is-operated 7 Without rotation of the cover; i a Fig. 2 is a transverse sectional view taken through the cover and upperportionof the pot aiid'showing the locking ring in elevation;

Fig. 3 is a'fragmentary sectional View taken on th'e line S -3 of Fig 2, showing the locking ring in' locked positionj. i

Fig. 4 is a sectional view similar to Fig/'2 but showing the locking 'r ing in unlocked position;

c Fig. 5. is asectional view taken onithe line:

ofFig. 4;

Fig. 6 is a. m n view of'the locking ring removed from the pot; f I

Fig. 7 ma fragmentary-sectional view partly in elevation taken-along the line 1 of Fig. 2 looking in thedirection of the arrows;

Fig. 8 is a fragmentary perspective viewv partly in elevation, showing the manner in which the lockingpins may be inounted in the grooveon thetop of. thepot; n ;1 Fig. 9 is a view similar to Fig. 7 but showing a nodificationof the cover and locking; ring; a

;;Fig. 1 0,is a fragmentarysideelevational view.

with a portion of. the-locking ring shown iYLSQC tionand illustrating a modifiedarrangement for the inner edge of the positively securing the locking ring in locked position;

Fig. 11 is a perspective view of two ends of a modified type of locking ring wherein the cover is rotated with respect to the pot to operate the locking ring;

Fig. 12 is a fragmentary perspective view of the upper portion of such pot;

Fig. 13 is a fragmentary, perspective view of a pot and cover in which the locking ring is moved to locking position by rotation of the cover with respect to the pot;

Fig. 14 is a plan sectional viewtaken on the line l ilt of Fig. 13 looking in the directionof the arrows and showing the'locking ring" in locked position;

Fig. 15 is a similar view, but showing the. cover rotated slightly in a counterclockwise direction and with the locking ring in unlocked position;

Fig. 16 is a sectional view taken on the line iii-l6 of Fig. 14; and

Fig. 1'7 is a sectional view taken on the line l'll'i of Fig. 15.

While my invention shows several minor modifications, it is illustrated in two main forms, namely, onein which the locking ring may be moved to or from locking position entirely independently of relative movement of the pot and cover and one in whichthe means for operating the locking ring to move it' to locking or unlocked position is associated with'and generally incident to relative rotation between the pot and cover. For convenience in illustrating the in-- vention, the first described embodiment utilizes the principle of operating the locking ring independently of movement of the cover with respect to the pot but it is to be understood that both major forms of the invention have certain advantages and one is not necessarily preferred over the other so far as the present application is concerned.

Referring now first to Figs. 1-8, inclusive, the

pressure cooker of my invention comprises a pot groove 2| in the not but capable of expansion into locking position within a groove 22 on the cover. Since this particular embodiment of the invention does not require rotation of the cover with respect to the pot, I find it advisable to provide means for preventing the cove from rotating with respect to the pot. Simple means comprise a pin 23 carried by one of the handles 24 of the cover and adapted to project/into an opening provided in the handle26 on the pot.

The locking ring [9 is provided with a number of internal edge recesses 27. recess 27 is generally radial while the other side is slanted to provide a cam surface capable of riding up onto pins 28 which, in the unlocked position of the locking ring, engage in the recess 21, but, in the locked position of the locking ring, engage against the inner peripheral'surface of the locking ring; One end of the locking ring is turned radially to provide a handle 29, this radial portion of the locking ring projecting through an edge recess 3| on the cover. The opposite end of the locking ring is adapted to engage a stop pin 32 which completely fills the groove 2 i. The edge recess 3! is wide enough to permit the necessary movement of the handle 29 to move the locking ring from unlocked to locked position, that is to say, from the position shown in Fig. 4' to the position shown in Fig. 2,

One side of each bo diment.

and, of course, in the opposite direction for again unlocking the cover from the pot. During the locking movement, the locking ring shifts bodily in a clockwise direction and, in so doing, rides up on top of the pins 28. This rotary shifting movement is, however, limited by the stop 32 so that in addition to movement of the ring as a whole, there is also an'expansion and separating of the ends to assure that all sections of the ring are expanded and all of the pins 28 are withdrawn from their corresponding recesses 21. While the locking ring will normally be held in expanded or locked position without special precaution, I utilize a sloping shoulder 33 behind which the radial portion of the locking ring is adapted to engage when in looking position, the action being for the slanting portion of the shoulder to deflect the radial portion of the locking ring slightly downwardly with the result that it will then spring up behind the square portion of the shoulder and lock the ring in position. It is shown in this position in full lines in Fig. 1. tion of Fig. 1 (the position of Fig. 4) it is simply necessary to deflect the radial portion of the locking ring slightly downwardly and then force the entire ring in a counterclockwise direction to again engage the pins 28 in the rece ses 2'! and unlock the cover from the pot.

In using the pressure cooker of my invention, the contents are placed in the pot with the re-' quisite amount of water, the cover placed in" position over the rim of the pot and down over the locking ring which, at this time, is substantially entirely contained within the groove 2! and the locking ring then moved by means of the handle 29 in a clockwise direction to expand the locking ring and positively lock the cover in place. and vapor generated within the pressure cooker forces the sealing ring [8 down tightly against the rim ofthe pot to cause a firm seal between the pot and cover. The pressure cooker is operated in the usual way with suitable pressure controlling, indicating and relief devices and when cooking has continued for anadequate length of time and pressure within 'the'pot reduced to a Safe value, the locking ring is returned to unlocked position and the cover lifted directly from the pot without need of rotating the same.

In Fig. 9, I indicate a modificationwherein the recess l3l, into which the handle projects,

extends only part way through the thickness of the cover and the radial-portion of the-handle I29 is downwardly'ofiset in the manner indicated-in the drawing.

used to'identify identical parts. Fig. 9 illustrates the manner in which the periphery of the covermay be left unbroken, for example, for decorative purposes or the like, and the pressure cooker in all other respects may be the same as in-the first described embodiment.

In the embodiment of the invention shown in Fig. 10, I utilize a not it and'cove'r i! with the same sealing and locking ring relationship as described in connection'with the main em- I provide in the recess 3i, however, a latch 35 in the form of a spring secured in position by means of screws 31; The radial portion of'the ring I9 is so related to the latch 36 that it may spring the same upwardly when moved to locked position and the latch will'the'n To return it to the dotted line posi--' Heat is applied. in the customary way.

In all other respects,'the' design may be identical with that shownin the preceding figures and the same numerals are spring downwardly behind the radial portion of the locking ring and hold it in locked position. In order to return the locking ring to unlocked position it is simply necessary to force the latch 36 upwardly using any suitable device for the purpose.

In the form of invention shown in Figs. 11 to 17, inclusive, the locking ring !9 has a radial portion 38 which engages into an edge recess 39 on the cover. In all other respects, the construction may be identical with that shown in the preceding embodiments and for convenience the same reference characters are applied to equivalent or identical parts. There are the same stop pin 32, pins 23, looking ring recesses 21 and sealing ring l8. In this form of the invention there must be a relative rotating movement between the pot and cover so that nothing equivalent to the positioning pin 23 (see Fig. 1) would be employed. When the cover is rotated in the direction indicated by the arrow in Figs. 12 and 13, the ring is caused to move bodily with respect to the pot until its end strikes the stop 32. There is then a positive expansion of the locking ring due to movement apart of its two ends in addition to the expansion caused by the locking ring engaging over the top of the projections comprising pins 28. Movement of the cover in a direction opposite to that shown by the arrow in Figs. 12 and 13 has the effect of unlocking the cover from the pot, but the functioning of the locking ring is the same as described in connection with the first embodiment.

This action of the locking ring, in response to movement of the cover, is best understood by reference to Figs. 14-17, inclusive. In Figs. 14 and 16, the cover has been rotated with respect to the pot in the direction indicated by the arrow in Fig. 1 3 so that the handles of the pot and cover are directly above each other and the locking ring assumes the position shown in these two figures. In Figs. 15 and 17, the parts are in the position in which the cover has been rotated in a counter-clockwise direction to return the locking ring to unlocked position. In Fig. 16, the locking ring is shown in a position between the two grooves in the pot and cover with the radial end portion 38 of the locking ring projecting slightly outwardly beyond the edge of the cover; while in Fig. 17 the ring is shown in only the groove 2| on the pot and the position of the radial portion 38 shows that the entire ring has contracted in the manner previously explained.

I have shown and described the several enrbodiments of my invention in order that those skilled in the art may understand how to practice the same but the invention is limited only by the scope of the claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In a pressure cooker, a pot and cover having a joint between them and oppositely positioned contiguous annular grooves, a locking ring normally contained in said grooves on the pot and having a plurality of recesses on its inner surface, a plurality of projections from the pot extending into said recesses, means including said cover for shifting the ringbodily to cause the said projections to ride outside the recesses and expand the ring, and a flexible sealing ring supported to engage said joint between the pot and cover.

2. In a pressure cooker, a pot and cover having a joint between them and oppositely positioned contiguous annular grooves, a locking ring normally contained in said grooves on the pot and having a plurality of recesses on its inner surface, a plurality of projections from the pot extending into said recesses, means responsive to relative rotation of the pot and cover. for shifting the ring bodily to cause the said projections to ride outside the recesses and expand the ring, and a flexible sealing ring supported to engage said joint between the pot and cover.

ALFRED J. KIRSTIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,137,085 Riddle Apr. 27, 1915 2,414,529 Ives Jan. 21, 1947 FOREIGN PATENTS Number Country Date 263,723 Great Britain Jan. 6, 1927 

